Correction: An earlier version of this article misstated where the Belmont Stakes is run. It takes place at the Belmont Park racetrack in Elmont, N.Y., in Nassau County, not the borough of Queens. This version has been corrected.

The rain was gushing sideways out of a deep gray sky as Victor Espinoza threw his left leg over American Pharoah and took his mount 10 minutes before post time for the 140th Preakness Stakes. Behind him, the beer-soaked infield at Pimlico Race Course, drenched in sunshine moments earlier, was being evacuated, and the giant white corporate tents were bulging and collapsing in the stiff wind. Thunder rumbled overhead. From the grandstand, the track’s backstretch was all but invisible.

Everyone seemed to be waiting for someone to pull the horses off the track, but no one did, so Espinoza and his remarkable horse went to work. From the dreaded No. 1 post position along the rail, Espinoza sent the Kentucky Derby champ and Saturday’s odds-on favorite almost immediately to the lead, sparing him the indignity of a face full of mud and daring any of the other seven horses and their jockeys to come catch them.

None could. What followed, as American Pharoah roared to a seven-length win over long-shot Tale of Verve in conditions that bordered on surreal, will be remembered here for years — especially if Pharoah, with two legs of the Triple Crown now to his name, makes history in three weeks in the Belmont Stakes. Since the last Triple Crown winner, Affirmed in 1978, 13 other horses have won both the Derby and the Preakness only to fall short in the Belmont, most recently California Chrome last year.

“He’s just an amazing horse,” said trainer Bob Baffert, who has now won six Preaknesses. “Everybody talks about his greatness, and it’s just starting to show now. To me, they have to prove it. Today, he did it. It was like poetry in motion.”

A summer-like day of sunshine and humidity gave way, at the worst possible moment, to gale-force winds and torrential rains. As he warmed up Pharoah on the track, Espinoza said he could feel his riding boots filling with water. Baffert could see a river of rainwater forming over the track. The announced crowd of 131,680 was nowhere to be seen, chased into the tents of the infield or the sheltered concourses inside.

“I’ve never been through anything like that,” Baffert said. “That was crazy.”

Track officials were monitoring the weather closely and believed conditions would not get any worse. Lightning strikes would have forced the horses off the track and into the paddock, but no lightning was seen in the immediate area.

“The horses were saddled, and with 10 minutes to post we didn’t want to bring the horses to the enclosed paddock for fear it might unsettle some of them,” said Sal Sinatra, Maryland Jockey Club general manager. “If conditions deteriorated, we were prepared to evacuate at any time. Fortunately . . . things slowly cleared up.”

Two weeks earlier, the Kentucky Derby had produced a gripping, three-horse duel, with American Pharoah chasing down Firing Line and Dortmund to win and raising expectations for a three-way rematch at Pimlico. But the sudden storm ruined any such hopes. Some of the horses, many of them inexperienced in these conditions, were clearly spooked. Firing Line, the second betting favorite, stumbled out of the gate and was never a factor. Dortmund, also trained by Baffert but for a different owner, overcame a bad start and stalked the lead for a time but never made a move.

“He didn’t like the sloppy track,” said Martin Garcia, Dortmund’s jockey. “He didn’t come out good from the gate, and he didn’t like the mud in his face. Not his best effort today.”

As the horses turned for the homestretch, American Pharoah — who had won the Rebel Stakes, a key Triple Crown prep race, on a sloppy track in March — had opened up a three-length lead, and most of the other horses appeared to be going backward as he surged forward.

“I had a great trip,” said Corey Nakatani, jockey for Mr. Z, who finished fifth, “other than I felt I should’ve been on a shark or a dolphin.”

On the homestretch, Tale of Verve caught and passed Divining Rod by a length for second place, but afterward, Dallas Stewart, the runner-up’s trainer, was effusive in his praise for American Pharoah.

“What a horse,” Stewart said. “He’s a tremendous horse. He’s getting better all the time. I think this validated what he is. He’s an improving horse. It was a wonderful run.”

Baffert trained three of the 13 horses since Affirmed who went to Nassau County with a shot at the Triple Crown but came up empty, losing with Silver Charm in 1997, Real Quiet in 1998 and War Emblem in 2002. For the next three weeks, the sport will be dominated by a single question: Is American Pharoah the one? The wise guys will say the Preakness, with its fluky conditions and the slowest winning time in 59 years, proved nothing — but Pharoah’s connections believe otherwise.

“The sign of a good horse is no matter what is thrown in his face he finds a way to win,” said Ahmed Zayat, American Pharoah’s owner. “God willing, he comes out of this race well, and we could be talking about history.”